Stamp for crushing ores.



No. 542,!52. Patented lab. 30, I900. F. A. PARNELL.

STAMP FDR CRUSHING Ma's.

(Application filed Dec. 28, 1897.) ,No Model.) 2 $heats-$h86t I.

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No.- 642,52. Patented Ja n. 30, I900. F. A. PARNELL.

STAMP FDR CRUSHING (IRES.

(Application filed Dec. 28, 1897.) (No Model.) 2 Sheets-Sheet 2.

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$ 5144 JZVWM MW Nrtzn STATES PATENT OFFICE.

FREDERICK ALEXANDER PARNELL, OF LONDON, ENGLAND.

STAMP FOR CRUSHING ORES.

SPECIFICATION forming part of Letters Patent No. 642,152, dated January 30, 1900.

Application filed December 28, 1897. Serial No. 663,821. (No model.)

"0 (all whom it may concern:

Be it known that I, FREDERICK ALEXAN- DER PARNELL, a subject of the Queen of Great Britain and Ireland, and a resident of No. 10 New Broad street, in the city of London, Eng land, have invented certain new and useful Improvements in and Relating to Stamps for Crushing Gold and other Ores, (for which I have obtained a patent in Great Britain, No. 7,300, dated March 20, 1897,) of which the following is a specification.

This invention relates to stamps for crushing gold and other ores, and has for its object to provide means whereby the ores may be more rapidly and efficiently pulverized to the required degree of fineness and at the same time the weight of and space occupied by the plant are reduced and less power is required for driving.

According to my invention I cause the stamps to exert upon the ore under treatment a rotary and grinding action as well as and simultaneously with a percussive action at each blow; and my invention comprises means for effecting this with simplicity and certainty. It comprises also means for insuring an efficient steam-tight joint for the pistonvalve under all conditions of wear and tear.

In carrying my invention into effect I en1- ploy a light framework, preferably of steel and approximately of the form herein described and shown. On the base of this frame are mounted the stamp-boxes, and also the necessary uprights and cross-beam for carrying the stamp-actuating mechanism. This consists of a number of similar steam-cylinders, placed vertically one above each stamphead. Each cylinder is provided with a piston and piston-valve of the type hereinafter described, and each piston-rod is attached to its stamp-spindle by a taper coupling-clip, adapted to be disconnected when required. The piston is provided with ratchet-gear, by means of which an intermittent step-by-step rotary motion always in the same direction is imparted to it and to the stamp-head at each downward stroke or at each upward stroke, if required. Means are also provided for taking up as far as possible the effects of percussive shocks, disc, and for efficientlubrication of the working parts. The action of the piston is such also as to cause and corn trol the working of the admission-valve by the live steam or other fluid, thus insuring a positive working of the valve Without the aid of any extraneous gearing and an equally positive action of the stamp. This, however, forms no part of the present invention and is only described and illustrated in full explanation of the working of the invention.

In the drawings, Figure 1 is an end elevation, partly in section. nal section through one cylinder and piston, showing means for rotating the piston and other details. Fig. 3 is a section on line A B of Fig. 2. Fig. 4 is a section 011 line B C of Fig. 2. Fig. 5 is an enlarged cross-section through the piston-valve, showing jointingring. I

I employ a bed-plate A, to which is secured the stamp-boxes, which are preferably of the well-known California type, as illustrated at B, a vertically-arranged framing O O carrying the cross-beam D, to which the cylinders G and their gear are affixed. A plant may have any number of stamps and cylinders; but for the sake of brevity I will describe one element thereof. Each cylinderG is provided with a piston L, having a recess around same at 7, and a piston-valve V, contained in a valve-box H, connected by suitable couplings and pipes P P, as shown, for example, to the supply and exhaust pipes E and F, respectively. The piston L is in one with its piston-rod, the lower end of which is connected to the stampspindle S, carrying the usual stampshoe, by a suitable clip-coupling, such as S'. The stamp head or die S may be of any suitable form. The pistonvalve V normally lies in its lowest position, as illustrated in Fig. 2, in which position the passage 1 is open to the top of the cylinder, and on admission of steam through the main inlet g steam would pass through the passage 1 and cause the piston to descend. When it has arrived at bottom of its stroke, steam passing the top end of the valve V would flow through passage 6 and thence through main exhaust 3, thus clearing of steam the top end of the valve-box II, the piston being then at the bottom end and ready for the return or up stroke. Live steam then passes through Fig. 2 is a longitudithe clearance-passage 5, raising the valve to top of its stroke, opening live-steam port 2, and admitting steam to the bottom of piston and raising same. The exhaust from the ends, respectively, of the piston-valve V escapes through passages 6 6 into the pistonrecess 7, thence through the passages 8 and S to atmosphere, and the above cycle of operations will continue while stamp is at work.

I will now describe the means for imparting the required intermittent step-by-step rotary motion in one direction to the piston. This may be arranged to take place at each stroke, whether it be an upward or downward stroke; but I will describe it as occurring on the downstroke. In the upper end of the piston L is a recess Z, in which is screwed a rifled nut L. Through the nut L works a rifled bar R, provided with collars r 7', which are supported by the ring Z in such manner that the bar R is free to rotate. To the upper part of the rifled barR is fitted a ratchet-wheel M, Figs. 2 and 3, secured by a nut r just below the cylinder-cover L The rotation of the ratchetwheel is maintained in one direction only by the stop-pawls m 'm, which are always passed into engagement by the springs m, Fig. 4. Thus the rifled bar R is prevented from rotating on the downward stroke of the piston by the pawls m, and hence the piston itself must rotate; but the rifled bar is free to ro tate during the upward stroke of the piston. Obviously by reversing the position of the ratchet and pawls or by reversing the hand ofthe rifling of the bar R and nut L the partial rotation of the piston L may be made to take place during the upward instead of the downward stroke.

q q are races for lubricant, provided with stop-studs g.

g Q2 are rubber ring cushions for obviating shocks.

Referring to the means for insuring tight jointing for the piston-valve V, hitherto semicircular rings, such as y, have been employed; but experience has shown that owing to working conditions they do not remain steam-tightbecause they wear at the lower parts y y to such an'extent as to prevent them springing up at the crown of the ring 1 whereat consequently leakage occurs. Now according to my present improvement to overcome this defeet I use in combination with the semiring y a small spiral spring .2, fitted into a recess 2 in each end of the piston-valve and interposed between same and the crown of the ring, and the spring by pressing up the crown of the semiring insures a steam-tight joint, because the live steam or other fluid-pressure itself serves to keep the lower or unringed portion of the valve tight, and'the semiring when constantly pressed up by the spring 2 described serves to make up for any wear that may take place.

My invention produces by very simple means a result as to rapidity and economy of production never before obtained in stamps.

. the stress in the frame.

The improved stamp has all the advantages of the cam-operated stamps and the more modern steam-operated stamps, securing the quickness and rapidity of blows and the cushioning effects of the latter, while producing a superior result both in quantity and quality than obtained from either class of earlier stamps.

The improved means employed by myinvent-ion involve the advantages of light weight, high crushing power, and maximum reduction of slimes. Further, the crushings are turned out with more regular and even consistencies than ever heretofore produced with any character of stamp.

All prior stamps run about ninety-six blows per minute and produce a large proportion of mud and slimes, which are difficult and eX- pensive to treat. This is due to the fact that very ponderous dead-weight blows do more work than is actually requiredviz, they crush only a portion of the ore to the required size and the Whole of the remainder into impalpable powder, which forms the objectionable slimes and mud.

Now my stamp by delivering a rapid series of light and somewhat resilient or knapping blows (from about two hundred to three hundred per minute) effects a progressive or gradual reduction of the ore to just the size required, and then it is at once washedaway by the water-service and is not further reduced, or at any rate a very small proportion, if any, is further reduced to that fine state which produces slimes and mud. The mechanical efficiency of my stamp is, therefore, much greater than that of former stamps, since practically the whole power is employed in doing useful work and little or no power is absorbed in the formation of productions necessitating specialandcostlytreatment. Further, in old stamp-mills there is an enormous amount of unavoidable vibration due to the ponderous blows, and this always produces such a crystallization of metallic frames when these are used as to render them useless in a very short time. Hence itis necessary to employ timber frames the weight of which renders transportation difficult. In my stamp the metallic frame can be used with success, and one which is light, cheap, durable, and portable and which may be made and exported with the complete plant. The reason of this is that the high speed better balances Comparing mine with former stamps as to power for power, great economy of stamp is attained in my stampmill owing partly to the lightness of the moving parts and partly to the absence of friction. This stamp economy amounts to about fifty per cent. as compared with the usual type of gravitation-stamp mill, and of course leads to a reduction of boiler-power and weight of plant. Owing to the lightness of my plant it is easy to transport, subject to less wear and tear, avoids need of heavy foundations, and decreases the cost of production.

IIO

Actual use of my stamps proves all the above advantages to be absolute facts. These advantages appear to be due to those features of improvement which result in running at a higher speed and delivering a rapid succession of comparatively light knapping blows as compared with slow-speed heavy rectilinear blows of former stamps. The improved blow obtainable by my invention combines a direct and a twisting motion with a light quick stroke. Thus the direct crushing effect is supplemented by a grinding effect, so that the ore is simultaneouslysubjected to two crushing forces, the one parallel with the axis of the stamp and the other angular to the first. The effect on the ore is peculiarly advantageous, greatly increasing the speed of crushing and diminishing the proportion of slime. By actual comparison between the results obtained with my improved stamps and those obtained under like conditions with prior stamp-mills there is an advantage of approximatelyiiftyper cent. in favor of my improved stamp.

I am aware that in rock-drills it has been usual to reciprocate the drills with a steam cylinder and valve and to revolve the drill with a step-by-step motion to successively present the edge of the tool to different portions of the surface being drilled; but there is a great difference between the rock-drill and an ore-crushing stamp, the drills always requiring rotation if a round hole is to be bored and stamps never having before been thought to require rotation on the downstroke for any purpose. 1 am also aware that it has been customary to operate stamp-mills by steam, and also that a steam-operated stamp has been turned step by step on its upstroke to equalize wear on its piston. I do not claim either a rock-drill or a steam-operated stamp-mill broadly; but

\Vhat I do claim is 1. In stamps for crushing ore and the like, the combination with a shoe, a cylinder, a piston in said cylinder, connected to said shoe for reciprocating it, means for revolving said piston, suitable valves and passage-ways for supplying pressure in said cylinder, a crossbeam connected to said cylinder intermediate of its ends and at one side of its longitudinal axis, and a frame consisting of braces having parallel upper portions connected to said cross-beam, and separated lower portions connected at their extremities to said base respectively in front and in rear, substantially as and for the purpose set forth.

2. In stamps for crushing ore and the like, the combination with a shoe and a base A, of a frame 0 rising from said base and consisting of inclined braces connected together at top and diverging at bottom, and respectively connected to said base at front and rear, a cross-beam D carried bythe upper side of said frames at one side of the vertical axis of the die, a cylinder G carried by said crossbeam, a piston L in said cylinder, connected to said shoe for reciprocating it, and means for revolving said piston, substantially as and for the purpose set forth.

3. In an ore-crushing stamp, the combination with a cylinder and reciprocating piston, and piston-valve having semicircular piston-valve rings, of spiral springs interposed between the ends of said piston-valve and the crowns of the semicircular rings, as and for the purpose set forth.

In witness whereof I have hereunto set my hand in presence of two witnesses.

FREDERICK ALEXANDER PARNEIIL- Witnesses:

J os. C. CHAPMAN. FRED O. IIARRIs. 

